1. Technical Field
The present invention relates to a liquid ejecting head that includes a piezoelectric element having a piezoelectric layer formed of a piezoelectric material and an electrode and discharges droplets from a nozzle opening, a liquid ejecting apparatus, and a piezoelectric element.
2. Related Art
As a piezoelectric element used in the liquid ejecting head, there has been a piezoelectric element that is configured so that a piezoelectric layer formed of a piezoelectric material exhibiting an electromechanical conversion function, for example, a crystallized dielectric material is interposed between two electrodes. Such a piezoelectric element is mounted on, for example, a liquid ejecting head as a bending vibration mode actuator device. Herein, as a representative example of the liquid ejecting head, for example, there has been an ink jet type recording head in which a part of a pressure generating chamber communicating with a nozzle opening that ejects ink droplets is constituted by a vibration plate, the vibration plate is deformed by the piezoelectric element, and ink in the pressure generating chamber is pressurized and is discharged as ink droplets from the nozzle opening.
The piezoelectric material used as the piezoelectric layer forming such a piezoelectric element requires high piezoelectric characteristics, and lead zirconate titanate (PZT) is adopted as a representative example of the piezoelectric material (see JP-A-2001-223404). However, lead zirconate titanate contains lead, and from the viewpoint of environmental problems, there is a need for a piezoelectric material that does not contain lead. Thus, as a piezoelectric material that does not contain lead, a bismuth-based piezoelectric material, for example, a piezoelectric material having a bismuth ferrate based (BiFeO3-based) perovskite type structure containing bismuth and iron has been suggested. As a specific example, there is a complex oxide expressed by a mixed crystal such as Bi(Fe,Mn)O3 and barium titanate such as BaTiO3 (for example, see JP-2009-252789).
In a non-lead piezoelectric material that does not contain lead, in order to obtain displacement that is equal to or greater than PZT, it is almost always necessary to apply a high voltage. However, if a high voltage is applied, in some cases, dielectric destruction may occur, and thus, higher voltage endurance is demanded.
In addition, of course, such a problem is also similarly present in other liquid ejecting heads that discharge liquid droplets other than ink as well as the ink jet type recording head, and is also similarly present in the piezoelectric element used in other devices than the liquid ejecting head.